Year	Total
1971	1499000000
1972	1778000000
1973	1813000000
1974	2046000000
1975	2441000000
1976	2418000000
1977	2731000000
1978	2685000000
1979	2837000000
1980	3011000000
1981	3232000000
1982	3476000000
1983	3639000000
1984	3639000000
1985	3732000000
1986	3964000000
1987	4302000000
1988	4267000000
1989	4092000000
1990	4267000000
1991	4859000000
1992	4336000000
1993	4557000000
1994	4743000000
1995	4934000000
1996	5394000000
1997	5674000000
1998	4688000000
1999	4730000000
2000	5035000000
2001	5279000000
2002	5612000000
2003	5899000000
2004	6413000000
2005	7005000000
2006	7880000000
2007	6395000000
2008	6952000000